Animals are susceptible to both external and internal parasitic infection and disease. This is especially true in an agricultural environment where a high concentration of animals means that infection and reinfection can easily occur. Parasitic and disease loads on livestock are known to be responsible for a number of conditions such as poor growth, anaemia, scouring, indigestion, poor feed conversion, depression and premature death. These conditions hamper meat production and quality and have a detrimental economic impact on both the farmers and the industry in general.
In order to address this problem, therapeutic agents including vaccines, antibiotics, anthelmintics (also known as anthelmintics) and other anti-pathogenic agents have been used to control disease and the numbers of parasites in and on livestock. Therapeutic agents come in a number of forms, including drenches, pour-ons, wipe-ons, injectables, oral dosages or slow release compositions and are used to prevent, control or eliminate internal and external parasites and disease. Therapeutic agents and especially vaccines, antibiotics and anthelmintics are now well recognised as essential to healthy livestock growth.
However, therapeutic agents have disadvantages in that targeted organisms have been found to be developing resistance. One method used to tackle the increase in resistance has been to increase the number of doses and amounts of the agents administered to livestock.
It has also been shown that increasing agent use can, in and of itself, cause further resistance to the agents to develop.
As a result of increased agent usage, the costs of achieving the same disease or parasitic control per head of livestock escalate because of both an increase in labour and an increase in the amount of agent needed. A further problem encountered with more frequent use of some therapeutic agents is the build up of chemical residue within livestock, making the meat worth less and, in some cases, not fit for human consumption. Animals also suffer an increase in handling stress due to the need for increased handling to administer the agents more frequently.
It is also known in the art that handling stress is a contributory factor in livestock weight loss. This, in turn means that livestock use more pasture for less of an economic return. This problem has been found to be particularly acute in animals which have a propensity to be easily stressed.
Clearly, many of these disadvantages could be addressed if animal stress levels could be reduced and the efficacy of therapeutic agents administered could be increased.
U.S. Pat. No. 4,046,890 discloses a pharmacologically active group of benzodiazepine derivatives said to exhibit anthelmintic, anticonvulsant, sedative, and muscle relaxant activity. There is no suggestion that this multiplicity of properties is particularly advantageous, that anthelmintic effectiveness is superior to that of other anthelmintics, nor any suggestion that production gains were achieved using these compounds.
Nutritional supplements have been proposed for use in reducing the effects of stress on animals. Examples of such supplements are described in U.S. Pat. Nos. 5,505,968 and 4,600,586. U.S. Pat. No. 5,505,968 discloses a supplement comprising a combination of tryptophan, electrolytes, and amino acids. By improving animal nutrition the effects of stress on meat quality degradation, and loss in liveweight are said to be reduced. The composition does not treat stress per se. There is no suggestion to use the composition with therapeutics such as anthelmintics, nor a suggestion that production gains can be achieved with these supplements.
U.S. Pat. No. 4,600,586 similarly discloses a method for producing a feed supplement comprising primarily polyethylene glycol and molasses for use in reducing “lot adaptation stress”. Minor ingredients are mixed to homogenicity with an effective amount of polyethylene glycol, then added to molasses and remaining polyethylene glycol. It is stated that if not mixed this way, that is, if merely admixed, then the composition is not effective to treat adaptation stress. Reduction in stress is achieved through increased metabolic utilisation of nutrients. The use of anxiolytics per se is not taught, the compositions are not suggested as being generically useful to treat stress. There is no suggestion that broad based production gains can be achieved using the nutritional supplement. There is no discussion of the combination of the supplement with anthelmintics or other therapeutic agents.
The applicants have now surprisingly found that antistress agents, and combinations thereof, when administered to an animal can generate a broad range of production gains in that animal. This property of antistress agents has not previously been recognised. Moreover, the applicants have also found that selected antistress agents, and combinations thereof, when administered to an animal can generate a broad range of production gains in that animal beyond what might be anticipated from reduction in stress alone.
Moreover, the applicants have also unexpectedly found that selected antistress agents when combined with therapeutic agents can increase the efficacy of the therapeutic agent in a synergistic manner.
An object of the present invention is to provide methods and agents for promoting production gains in animals or at least provide the public with a useful choice.
Other objects will be apparent from the statements and disclosure which follows.